There are numerous different types of steam generators used for multiple functions. One such function is use in a pressurised water reactor (often referred to as a PWR). When used in a PWR, primary coolant is used to transport heat between a reactor core and a steam generator. In the steam generator, the primary coolant is cooled by a secondary coolant, or in other words a secondary coolant is heated and converted to steam by the primary coolant. Once heated, the secondary coolant is used to turn a turbine which is connected to a generator to generate electricity.
Generally, the steam generator will include a bundle of tubes at least partially contained within a vessel. The primary coolant may be supplied to the tubes and the secondary fluid may be supplied to the vessel, or vice-versa. The wall of the tubes separates the primary coolant from the secondary coolant, which is of particular importance because the primary coolant may be radioactive. As such, when designing a steam generator it is important to ensure that the integrity of the conduit is not compromised.
Large steam generators, particularly those of PWRs, require a large surface area to meet the heat transfer requirements; as such a large number of tubes and/or large lengths of tubes are required. This means that the design requirements on the tubes for a steam generator, and the transport and installation of a steam generator can be complex and costly.
Furthermore, a compromise often needs to be made between performance of a steam generator and design parameters such as tube geometry, size and materials.